The present invention relates to a cooled turbine rotor wheel, and in particular, a high-pressure turbine rotor wheel for an aircraft engine.
Turbine performance largely depends on the turbine entry temperature of the working medium. The level of this temperature is, however, limited by the thermal loadability of the material of the turbine rotor blades. Therefore, the turbine rotor blades must be cooled as effectively as possible in order to minimize their thermal load and ensure maximum life. The high-pressure blades of a turbine rotor wheel usually possess internal cooling channels. For the cooling of the rotor blades, high-pressure cooling air is fed to the turbine rotor wheel through high-pressure cooling channels originating at the blade root. To provide a seal against the hot-gas duct downstream of the stator, so-called sealing air is used which also flows the disk rim and the interspace between either of the adjacent blade necks of the turbine rotor blades and which is fed through low-pressure channels originating at the blade neck to cool the blade shrouds or other blade areas with lower supply pressure requirement. The temperature of the sealing air is, however, so high that, in particular, the disk rim of the turbine rotor wheel, but also the blade platform and the blade neck, are subject to such a thermal load that the life of the turbine rotor wheel, which comprises the disk and the rotor blades, is considerably reduced.
In a cooling system for a turbine blade disclosed in Specification U.S. Pat. No. 3,834,831, a perforated cooling chamber, which is supplied with cooling air, is situated in a cavity provided in a blade neck and in the interspace between either of the blade necks of adjacent turbine rotor blades. The cooling air passes through the perforation to the inner walls of the blade neck and radially flows through the blade via cooling channels originating at the cavity in the blade neck. The cooling air supplied separately via the perforated cooling chamber situated between the blade necks cools the outer side of the blade necks as well as the free periphery of the disk rim and leaves the interspace via a gap between the adjacent blade platforms. This cooling system for a turbine rotor wheel is, however, disadvantageous in that the plurality of cooling-air supplied cooling chambers situated on the disk periphery and in the cavities of the blade necks requires considerable investment.